Typewriting machine



Sept. 13,` 1932.

w. A. DoBsoN TYPEWRITING MAGHINE Filed Deo. 2z. 195o Patented Sept. 13, 1932 UNITED STATES PATENT OFFICE-@fi WILLIAM A. DOIBSON, OF BBIDGEPORT, CONNECTICUT, ASSIGNOR TO 'UN1311111511700D.

ELLIOTT FISHER COMPANY, or Nnw YORK, N. Y., A CORPORATION or DELAWARE v TYPEWRITING MACHINE Application-'med December 23,` 1930. Serial No. 504,275.9.

This invention relates to the platenerelease mechanism of typewriti'ng machines. An object of the invention is rto provide a mechanism that is compact, light, durable and cheap, for portable typewriters.

rl`he usual carrying case is placed over the entire typewriter, thereby limiting the length of the typewriter-carriage, and precluding the use ofthe well-known platen-releases, since they extend considerably beyond the ends of lthe carriage.

In the present invention, the entire mechanism may be compactly housed within the platen. The linespace wheel and its related parts retain their old positions, and need not be altered, and thev typewriter-carriagey does not have to be lengthened.

A cam is made fast to a slidable platenshaft, and spreads apair of levers, which i are connected to the line-space wheel, said levers acting upon brake-shoes, and thereby normally clutching the platen to the linespace Wheel; Release of the clutch is effected by pulling out the platen-knob.v

The clutch-mechanism is securely retained in effective position, so that jarring of the platen during case-shifting and carriage-return movementscannot accidently release it. For this purpose, the clutch-operated cam maybe provided with two camming surfaces inclined in opposite directions. When the cam is moved to its effective position, the clutch-levers ride upv on one of the surfaces, thereby making the clutch effective. Further movement of the cam slightly fiexes Vthe levers as they ride over the top of said cam onto the oppositely-inclined surface. The levers when in -this position prevent the cam from being accidentally moved back to release the platen-clutch, since the initial return movement of the cam must first flex the levers before effecting their release.

Other features and advantages will hereinafter appear.

In the accompanying drawing,

Figure 1 is a front view, part-ly in section, of a platen and its appurtenances, with the clutch in released position.

Figure 2 is similar to Figure 1, but shows the clutch closed.

- Figure 3. is a perspective view of vention, with parts disassembled.

Figure 4 is a sectional side viewtaken along line 4-4 of Figure 1. i

Figure 5 is a perspective view of the inven` tion, with parts broken away for clearness.

" igure 6 is a sectional side view taken along the line 6-6 lof Figure 1. Y V- A platen 10 is rotatably supported by means of right and left hand'platen-shafts o0 11 and 12, mountedin carriage-end plates 13'. Theright-hand platen-shaft 11'has a knob 14 fixed by screw 15. l This shaft is compara-y tively short, and extends inwardly through4 a hub 16 on the'carriage-end'platc 13 and into a hub 17 that forms part of platen-head 18 rigidly attached byscrews 19. A screw 20 fixes shaft 11 tothe hub 17.

The left-hand platen-shaft 12 is slidably mounted within the platen, and is supported at its inner end in an extension 21 of hub 17. The outer end of the shaft 12 has al bearing in the n- A l the carriage-end plate 13 and carries at its extremeend a'knob22 rigidly attached by screws 22a. The innerl end of the shaft 12 is provided with Vflattened sidesV 23 tofiit in a keyway 24 in the extension 21.` The knobV 22 is thus connected to either rotate the extension21, together with the platen 10, or to move the shaft endwise to operate aplatenrelease mechanism, as Vwill be described later'.

A line-space wheel 25, loosely mounted on kthe shaft 12, is vnormallyclutched to they diametrically opposite, and the slots 32 are directly in line with the slots 33. The disks areY spaced apart and may be formed of a Vsingle piece of metal which also includesa hub 34a through which the platen-shaft-12 extends. p The levers 31 are rectangular in cross-sec 35, and prevents any endwise movement of the levers.

A pair of clutch shoes or bands 37, in the form of cylindrical segments, overlie said levers 31 and iit in the space between the disks 34 and 35, which prevents said bands from sliding endwise along the levers. Pins 38 fixed to the disk 35 extend into openings 39 in the disk 34. The ends of the shoes 37 rest on said pinsV 38 and Aare thereby prevented from turning with respect to their operating levers `31, so that the relative positions between the clutch-shoes and the levers remain the same at all times.

The disks 34 and 35,"together with the clutch-shoes 37 and levers 31, aresupported on the platen-shaft 12 and itinto Va metal shell 40 rigidly attached to the platen 10 by screws 41. f -The line-space wheel 25 is mounted on the hub 34a and is iiXedto the disk 34 by four screws 42. The line-space wheel is of a 'greater diameter than the platen-shell 40, andl when the clutch-parts 31, 34, 35 and 37 are inserted into the platen-shell 40, the linespace wheel 25 will abut the outer end of said shell and will thereby act as a stop to prevent the aforementioned clutch-'parts from being inserted too far into the platen. Y

'The'line-spaoe wheel is provided with a ledge 43 extending into the shell and is of substantially the same diameter as the inside diameter of said shell, to thereby form an end bearing for the left end of rthe pla-ten 10 upon the shaft 12. The right end of the platen has its bearing on the shaft 11 by means of its end plate 18 and hub 17.

The levers 31 when released just touch the shoes 37 at their mid-sections, and allow the platen to rotate freely, while the line-space wheel 25 is held stationary by means of its usual spring-detent roller 44. v v

After the work-sheet is positioned, the knob 22, together with the shaft 12 and cam 26, is pushed endwise towards the right until the knob abuts against the end plate 13 (Figure 2). This forces the cam 26 under the levers 31 to wedge them outwardly. At this -timethe bottom of the slot 32 in the disk 34 acts as a fulcrum for the ends of the levers 31, thus forcing outwardly their intermediate sections which engage the inner surface of the bands 37. These bands in their ineective positions lie close to the inner surface of the shell 40, which forms part of the platen 10,

and lany outward movementk of the levers 31 will cause the shoes 37 to bind tightly against the inner surface of the shell 40,` thereby clutching the platen rigidly to the line-.space wheel to compel them to rotate together.

Y It will be seen that the clutching of the line-space wheel and platen is eective because the pins 38 are iiXed to the disks 34, 35, which in turn are rigidly attached to the line-space wheel 25 and prevent rotation of the bands 37 except in unison therewith.

lVhen it is desired to disconnect the platen from `the line-space wheel, the knob 22 is pulled out to the left until the end 45 of the cam 26 abuts against the hub 34a, which is backed up by the carriage-plate 13, so that the impact caused by the end 45 striking the hub 342L will be completely taken up by the rigid end plate 13. In this position the cam 26 is fully withdrawn from the ends 30 of the levers 31, allowing them to move back to their normal positions and lie idle on the platenshaft .12, .and thereby release the bands 37 from the platen-shell 40.

To prevent the clutch from becoming accidently disconnected by the jarring of the platen during carriage-returning and caseshift movements, the cam 26 has an opposite inclined adjacent surface 46, whose inclination is much less than that of 26. Endwise movement of the cam 26 from its ineffective to its effective position will irst cause the ends 30 of the levers 31 toride up on the camsurface 26 to spread them apart and bind the clutch-shoes 37 against the platen-shell 40. Further endwise movement of the cam 26 to the right will cause the levers 31 to be slightly flexed just as they snap over the top of the cam 26 onto the opposite inclined surface 46. l It will therefore be seen that jarring of the platen will notl accidently release the clutch-mechanism, since it is necessary to flex the levers 31 in order for them to ride off of the surface 46 and onto thecam-surface 26.

Itis also to be noticed that inthe present invention the parts can readily be assembled and disassembled without the use of any special tools.

In assemblingv the present invention, the sha-ft 12, together withv its cam 26, is rst mounted in the Splaten, which includes the shell 40, the end plate 18, and the extension 21. rlhe flat sides 23 of the shaft 12 are inserted in the key-way 24 .and the hub 34 carrying the disks 34, 35, and the line-space wheel is then placed upon the shaft 12. The levers 31 are inserted in slots 32, 33 with the wide parts 36 lying betweenY the disks 34, 35, and the bands 37 are placed between the disks 34, 35, .and overlie the wide part 36 of the levers 31. The shaft 12, together l with all the parts carried thereby, is now moved endwise to position them within the platen-shell 40. The line-space wheel abutting the end of the shell will determine the relative positions of the parts with respect to the platen. j

The clutch-parts are 'retained within the platen by the disk 35, which just fits within the shell 40. rlhe outer rim 47 of the disk lies close to the inner side of the shell 40,

and is provided with a groove 48 to co-operate with lingers 49 extending into the groove through o-penings 50 in the shell 40. The fingers 49 are formed by bending over the ends of a flat spring 51. The spring is clamped to the platen-shell 40 after the parts have been inserted therein. One of the ngers 49 is first hooked into an opening 50, and, since the untensioned spring is of smaller curvature than the shell 40, the spring will be tensioned in forcing it to conform to the curvature of the shell, to enable the other finger 49 to reach and snap into the other opening 50 in the shell 40. The lingers 49 and spring 51 in this position act in the form of a. clip, since the spring tends to return to its normal position, and in so doing presses each finger 49 against aside of its shell-opening 50, thereby holding itself fast to the platen-shell 40. The spring 51 extends less than half-way around the shell 40, so that when the clutch is released and the platen-shell and spring rotate around the disk 35, which is held stationary by the linespace wheel 25 and its detent-roller 44, it will be impossible for both'of the fingers 49 to be in the cutouts 33 of the disks 35. By this arrangement one of the lingers will always be in the groove 48, and effective to retain the parts within the platen.

The platen with its clutching mechanism is detachably mounted between the ends of the platen-frame in a portable typewriter, where very little room is available. There is used a sliding .shaft which projects through the end of the platen-frame, for controlling the clutch; the dismountingy and mounting of the platen being practicable even though the clutch-shaft projects through one platen-frame end. The clutch-shaft must be of small diameter, so that the platen may rotate freely. The platen-clutch and line-space wheel are coniined-between the platen and the left-hand platen-end 13, the platen being detachablymounted on said end by means of the endwise movable shaft 12, which serves as an axle for the platen; and finger-wheel 22 is detachably secured tothis projecting end. The clutch is controlledby the endwise movement of said shaft 12. In order to enable the nger-wheel 22 to rotate the platen, the shaft 12 is splined tohub 21 which is xed in the opposite end of the platen, this spline permitting shaft 12 t0 slide while remaining keyedto the platen (for rotating the latter whether the Vplaten is released from or clutched to the line-space wheel). The stub-shaft 11 extends from hub 21, and has a bearing in the right-hand platen-frame end 13, and carries at its outer end afinger-wheel 14, which is temporarily removable from said hub 21 by unscrewing the screw 20, so that the right-hand end of the platen may be temporarily dismounted from the right-hand platen-end 13. While the platen-end is -so dismounted, the shaft 12 may be displaced -to'the right, 'and may be pushed into the space which was formerly occupied by the stub-shaft 11, so that the left-hand end of the shaft 12 may be free" from the platen and platen-'frame end 13, whereupon the platen, clutch and kshaft 12 may be withdrawn as ay unit from the platenframe. f

To mount the platen, or to remove it from Vthe carriage, the knob 14, together with its shaft 11, is iirst removed from the platen by loosening the screw 20. The knob 22 is then 'its removed from its shaft 12, which is pushed .Y

completelyA into the platen, and the platen and clutch mechanism may be removed from the typewritencarriage. If it is desired to place the platen upon the carriage, the shaft 12 is aligned with its opening in the carriageend plate 13, and the shaft 11 is then inserted into the hub 17 to push" the shaft,12out through its end plate 13.l The platen is then moved to the left to bringV the hub 34a against the. end plate -13', and the shaft 12 is pulled out "until the end 45 of the cam 26 abuts against the hub 34a. Knob 22 may now be fixed to the shaft 12 by its screw 22a, and the shaft 11 fixed to the platen by the screw 20.

The platen and clutch are now mounted in tion of a platen, a slidable platen-shaft, a"

cylindrical disk loosely mounted on said shaft, a second disk secured to said first disk and spaced apart therefrom, slots inv said disks, levers extending longitudinally of said platenv and resting loosely in said slots, a cam iixed'to said slidable platen-shaft and located adjacent the end of said levers, a linespace wheel attached to one of said disks, and clutch-bands resting on said levers and within said platen, so that when said platen-shaft together with said cam is moved inwardly said clutch-bands will vgrip said platen 'to cause said line-space wheel andk platen tov rotate together.

2. In a. typewriting machine, the combinai tionofa platen, a platen-frame having ends, a. line-space wheel, a releasable platen-clutch, said clutch and line-space wheel being confined between the platen and one of said Y.

ends, means for detachably mounting an end of sadplaten upon an end of said platenframej said mounting vmeans `including an endwvlse movable shaft Journaled 1n an end of the platen-frame and havlng a fingerf Wheel detachably mounted upon its outer end,

said clutch being controllable by endwse movements of said shaft, a hub Xed to the opposite end of the platen, Said endvvse movable shaft having a spline connection to Said hub and being sldable for operating the clutch While connected to said hub'to rotate the platen, and a stub-shaftextendng from said hub and having` a bearing n the opp0- site platen-frame end, and carryingl at its outer end a finger-Wheel said stubshaft bengtemporarly removable from said hub for assembling or disassemblng the platen upon the platen-frame, said sliding shaft being dsplaceable through said hub sulloently to'dsmount the platen at its first-mentioned end, While the other end s ln unmounted oonditon by reason o1 the removal of said stubshaft from said hub.

Y WILLIAM A. DOBSON. 

